Major appliances, such as automatic clothes dryers employ coil type heating elements that must be mounted in appropriate locations within the dryer structure. Generally, these heaters are formed by passing the coil element through ring or grommet type insulators generally made of porcelin and the like which in turn are supported by some form of metal support member that is secured in the proper location on the wall of the dryer. For example, the support member for the insulator may take the form of a wire formed into a U-shape with insulators supported at remote ends of the U and with the bridging section of the bracket secured by welding or generally by a sheet metal screw to the supporting wall. Such a device is shown for example, in Canadian Pat. No. 779,440, issued Feb. 27, 1968 to Himes.
It will be apparent that in the above patent the insulator is permanently fixed to the bracket so that the threading operation or mounting operation for the coil itself is relatively more complicated, i.e., the heating element cannot be effectively prethreaded by machine through the insulators unless a separate assembly step is formed after the brackets are mounted to the wall, i.e., the clipping of the insulators to the ends of the brackets which requires special manipulations and increases the costs. Alternatively if the insulators are premounted on the brackets then the heating element will normally be threaded through the insulators and assembly of the brackets with the heating element prethreaded becomes more cumbersome.
Canadian Pat. No. 260,881, issued May 18, 1926 to Weir discloses a coil element mounting arrangement wherein a ceramic element is fixed to the wall and is provided with a curved slot having an opening. The heating element may be passed through the opening into the undercut slot and retained therein after the insulators are mounted in position thereby facilitating threading of the heating element onto the assembled insulators.
Canadian Pat. No. 771,878, issued Nov. 14, 1967 to Kinney shows a system for clipping the insulator to a back wall using a mounting strip that is secured directly to the surface to which the heater is to be assembled.
Canadian Pat. No. 889,457 utilizes tabs struck out of the wall of the unit and fastens clips to which the insulating elements supporting the heating coil are mounted. This device facilitates mounting of the heating coil to the unit but incorporates a relatively complicated insulated unit having a pair of apertures. The bridge of each insulator extending between the two apertures is encircled by its respective clip structure that in turn is connected to its respective tab by a flange and a tongue threaded through an aperture in the tab.
Obviously such a structure is relatively expensive and does not provide a positive latch between its clip and tab, but does facilitate assembly.
Another type of mounting structure is shown in Canadian Pat. No. 1,017,786, issued Oct. 20, 1977 to Whiteman et al. In this device an insulator is mounted directly on the supporting structure via a projection extending through an aperture in the ceramic insulator. It utilizes a metal clip mounted on the ceramic insulator to hold the heating element in position. This structure is relatively weak and is expensive.